Speaker
Description
Significant shortcomings in the resolved resonance region of all existing evaluations of iron isotopes have been identified from leakage neutron measurements to be related to inaccurate elastic cross sections minima between 50 and 700 keV [1,2]. Those regions are only sensitive to highly accurate transmission measurements through very thick samples. The overestimation of the measured yield in leakage neutron measurements reach 30-40% around 300 keV. Similar disagreements have been identified from 50 up to 700 keV. Therefore, new transmission measurements are needed to improve the description of the measured minima of the total cross section. The total cross section in this energy range is dominated by elastic scattering, as the capture cross section above 70 keV is only a correction of the order 10$^{-3}$. We have measured the neutron transmission of 30, 50 and 90 mm thick iron samples with high statistical accuracy at the nELBE neutron time-of-flight setup [3] at Helmholtz-Zentrum Dresden-Rossendorf in 16.5 days of beam time. The neutron transmission was measured using a plastic scintillator in the energy range above 100 keV with a short flight path of 868 cm. The new transmission and total cross section data of iron can be used to improve the elastic scattering cross section minima in the INDEN-III (structural materials) evaluation of IAEA [4]. This project has received funding from the Euratom research and training programme 2014-2018 under grant agreement No 847594 (ARIEL).
1 B.Jansky et al., JEFFDOC-1918, NEA (2018)
[2] M. Schulc et al., App. Rad. and Isotopes 130 (2017) 224
[3] A.R. Junghans et al., EPJ Web of Conferences 239 (2020) 01006
[4] International Nuclear Data Evaluation Network on the Evaluated Nuclear Data of the Structural Materials, IAEA Vienna, 2018 INDEN-III
INDEN-III webpage
